The invention relates to a flow-channel wall for partial modification of the flow channel cross section.
Locally limited, adjustable, round or annular flow channels are known from DE-A-11 61 412, DE-A-17 04 850, DE-A-26 54 001 (corresponding to U.S. Pat. No. 4,279,857), DE-A-28 23 999, DE-A40 13 610 (corresponding to U.S. Pat. No. 5,110,518). Slotted flow channels, which may be locally deformed, are described in DE 44 00 069 (corresponding to U.S. Pat. No. 5,788,998) as well as in DE-A-195 35 930 (corresponding to U.S. Pat. No. 6,099,290) In case of round devices, the deformable area of the flow channel is designed in a single-walled manner. The use of this known device is limited based on its particular construction whereby relatively rigid single-walled ring elements are employed, which have to be deformed to a diameter in the range of larger than 100 mm through the use of screws. Smaller flow channel cross sections cannot be modified with these solutions (methods).
Should one want to additionally obtain locally limited large modifications of the flow channel cross section, as it is needed in practice, then these constructions are unsuitable as well because the obtainable absolute deformation of the ring elements is very small even at the most flexible solution with its approximately 200 micrometers (xcexcm) as disclosed in DE-A40 13 610. The reason for this is that one may deform the ring element only within their linear-elastic deformation range to ensure that they resume the exact original shape after resetting the adjustment element.
The ring element described in DE-A-11 61 412 has however the advantage that no sealing problem occurs at reduced flexibility using the described solution. The described solution in DE-A-26 54 001 (U.S. Pat. No. 4,279,857) and DE-A-28 23 999 are somewhat more flexible but have a certain degree of leakage as a trade-off since the rings must be displaced in the area of the sealing surface during adjustment. In addition, the rings create minor dead spaces within the flow channel while they are being deformed, which may lead to undesirable material stagnation and material degradation in the mass flow.
In DE-A-44 00 069 (U.S. Pat. No. 5,788,998), the deformable area in the slotted flow channel is also only single-walled. In contrast, in DE-A-195 35 930 (U.S. Pat. No. 6,099,290) there is a device described whereby the linearxe2x80x94elastic adjustment area is enlarged by the integration of a (metal) sheet stack into a flow channel. However, this known solution has weakness in relation to its production and mechanical stability. In terms of production technology, it is often very difficult or even impossible to weld a sheet stack to the desired location. The welding of very thin metal sheets, which would be especially flexible, usually creates problems. Whenever welding is principally possible, then unavoidable weld stresses occur during welding, which leads to distortion in many cases. Even in case of distortion-free welding, the deformation capacity of the sheet stack is reduced by the welding stress whereby the welding seam is additionally always a mechanical weak spot. Furthermore, the strength of the flow channel wall is limited in relation to the interior pressure (under which pressure lies the medium flowing through the channel) since only the so-called flow channel sheet is welded around its entire circumference to the flow channel body. The remaining sheets of the sheet stack contribute only marginally to the pressure resistance of the flow channel wall in the known solution since they are welded to the flow channel body only at one side of their four sides. We are dealing therefore with sheets (plates) that are mounted one-sided, seen in a static sense.
To this end, methods are employed in various industrial applications whereby it would be desirable to modify purely elastically particular areas of a flow channel in their geometry to the highest degree possible in an operating facility or during a running process without having to adopt the disadvantage of the known solution. It is therefore the object of the invention to provide a device of the generic type in such a manner that generally there is made possible, relative to the state-of-the art, an enlarged absolute adjustment area and larger relative adjustment in relation to close, neighboring areas of the flow channel geometry while having possibly additional greater interior pressure resistance. Thereby, it should be ensured at the same time that no leakages and no dead spaces can occur and that flow channels with very complex geometries (shapes) may be produced as well.
A device can be realized with the present invention with which a mass may be moved through a flow channel, for example, whereby during the flow through the flow channel, the flow velocity of the mass may be locally limited in a large measure either manually or by means of a guiding or control device, or the flow velocity may be altered by mere linear-elastic deformations of one section of the flow-channel wall. However, a prerequisite for this is that the local mass flow may be adjusted at particular locations in a desirable manner relative to adjacent flow channel sections.
This object is achieved according to the invention in that the flow-channel wall 9 consists of homogeneous material and is multi-walled at least in partial areas.
A wall area is thereby integrated into a flow channel whereby said wall area consists of homogeneous material and which is multi-walled in partial areas. Homogeneous material is to be understood in the framework of this application that the single-walled areas of the flow-channel wall and the individual walls of the multi-walled area consist of exactly the same material, whereby even in the transition areas from the multi-walled area to the single-walled area there are no non-homogeneous elements such as glued or welded seams, for example. Homogeneous, in the sense of this application, is also a wall that consists of multi-component material, such as CFK, as long as the composition of the flow-channel wall in the single-walled area is identical in the transition zone and in the multi-walled area. The material is also homogeneous in the sense of the application if one partial area of the single-walled flow-channel wall has been manufactured in one piece together with the transition area and one individual wall of the multi-walled area. In the sense of this application, a flow-channel wall is multi-walled when a cross section that is perpendicular to the flow direction, cuts through at least two individual walls. This multi-walled construction has the advantage that the flow-channel wall may be modified in a simple manner through variation of the thickness of the individual walls and the number of individual walls. Thereby, a varying strength of the flow-channel wall can achieved relative to the interior pressure of the flowing mass. Should one strive for extremely high flexibility, then one has to select extremely thin walls. Should the flow-channel wall have to additionally withstand a high interior pressure, then it is of advantage to choose a high number of individual walls in the multi-walled area and to increase thereby the total thickness D in the multi-walled area. The linear-elastic deformation area, and thereby the flexibility of the flow-channel wall, is reduced to a very low degree compared to designing the area in a single-walled manner with the same total thickness D since the maximum expansion occurring in the flow-channel wall at the same deformation is less than in the multi-walled case. In addition, the solution according to the invention has also the advantage that all individual walls are firmly connected at all sides to the bordering flow channel body whereby said individual walls can absorb pressure forces in the same manner as the flow channel (metal) sheet. In contrast to the state-of-the-art, the individual walls are walls that are firmly mounted at all sides.
Such flow-channel walls may be employed in flow channels for gaseous as well as liquefied mediums. One can adjust a wide air flow in its intensity and across it width very accurately, for example in a screen printing device, with which one prints a strip across a larger width, or one distributes fluid across a wider area. In the scope of printing technology, the distribution of the stream of printing ink, which flows through a slotted flow channel, may be adjusted by means of the inventive device in an ideal manner. Finally, there are many and diverse employment possibilities in processing of synthetic material by controlling the melt-flow distribution in a tool. Such flow-channel walls may be integrated into all conceivable flow channel geometries. However, the most common are slotted, round and annular flow channel geometries.
The flow-channel wall consists of homogeneous material and is designed partially multi-walled for the purpose of partial deformation. Such flow-channel walls can be advantageously integrated into tools wherein there is the requirement that the geometry of the flow channel provided in the tool may be specifically altered at certain locations.